The goal of this proposal is to develop and evaluate a quantitative myocardial imaging technique incorporating the simultaneous or concomitant use of both "hot" and "cold" spot nuclides. By using quantitative imaging the combined myocardial radioisotopic distributions of two or more radionuclides will allow generation of a series of isocount contour maps suitable for defining myocardial zones of myocardial ischemia, infarctions, and scarring. This type of analysis could be repeated at regular intervals in the clinical setting. Both animal and patient studies are planned. Dogs will undergo a closed chest infarct model.